Effect of Moisture Content, Grinding, and Extraction Technologies on Crude Fat Assay

Conventional breeding as well as transgenic approaches constantly strives to make improvements to quality traits such as increasing the percentage of oil and/or modifying the oil composition. One of the key challenges faced by the industry is obtaining accurate, cost-effective, and rapid analysis of oilseeds/grains with enhanced quality traits such as total crude fat (oil) content or a modified oil composition. Reliable crude fat analysis is of paramount importance to oilseed businesses because monetary assessment in the trade of such seeds is based on total oil values. Although several different primary and secondary technologies are available to determine crude fat content in oilseeds, there are significant variations in the results reported by different procedures. A comparative evaluation of different grinders (Mega-grinder, Knifetec, Cyclotec, Cemotec, Mikro mill, UDY grinder, Brinkmann-Retsch grinding mill) and commonly performed crude fat extraction methodologies [accelerated solvent extractor (ASE), supercritical fluid extraction (SFE), Ankom batch extraction, automated Soxtec extraction and classical Butt-tube] on the determination of total crude fat content in soybean seeds is presented. The results clearly suggest a need for harmonization of official primary reference methods across different organizations (e.g., AOCS, AOAC, AACC, ISO, DGF). This is vital for the development of rugged calibrations for nondestructive, high-throughput secondary procedures involving near infrared transmittance, near infrared reflectance/imaging, and nuclear magnetic resonance spectroscopy. Strategies aimed at harmonization of methods will aid in the development of successful business opportunities and obtaining fair trade value for the quality-enhanced traits in the global market. Recommendations for developing secondary calibrations and performing interlaboratory studies are also presented.